"It was a great pleasure to have shared all these years with you, (my) friend @neymarjr," he wrote.

Argentinian Messi and Neymar were the part of the famous ‘MSN’ trio with Uruguayan Luis Suárez, which many believe is the greatest front three in modern football. They have scored 250 goals collectively in their three La Liga seasons together.

Speculation has mounted in recent weeks that he was on his way out of the Nou Camp, seemingly tempted by a hugely lucrative offer and the chance to lead the PSG line.

Neymar was at the heart of Barcelona’s famous Champions League comeback against PSG last season, when the Spanish giants overturned a four-goal first-leg deficit to win 6-1 at the Nou Camp and 6-5 on aggregate.

He scored twice in that game and set up the winner, in a performance that will have done much to convince the French team to smash the world transfer record to sign him.

Neymar would also bring huge commercial value to PSG, with his almost 80 million Instagram followers and 30 million followers on Twitter.

PSG are bankrolled by their deep-pocketed Qatari owners, although some have questioned how the club could afford the deal without falling foul of Financial Fair Play regulations.

There are also reports that Barcelona will issue a complaint to UEFA over the transfer. PSG insist that they are fully complaint with UEFA regulations, although there are suggestions they could sell players to make way for Neymar’s arrival.